The present invention generally relates to a plug-and-play (PnP) interface circuit for computers or microprocessor-based systems, and in particular to a PnP interface circuit incorporating a visual display device for displaying communication port information associated with a peripheral device connected thereto.
Nowadays, computers play a very important role in the fields of information processing, management and control. Besides the central processing unit (CPU) that performs arithmetic operation and executes commands, the architecture of a computer also includes peripheral devices for input/output operations, such as keyboard, joystick, modem, printer, scanner, card reader and bar code reader. Each of the peripheral devices is connected to and communicates with the CPU by means of an interface circuit formed as an interface card. The most common interface cards available in the market are RS-232 and RS-422.
With the development of the computer technology, the traditional interface circuits are gradually replaced by more user-friendly interface circuit, such as Plug-and-Play (PnP) interface circuit, for example Universal Serial Bus (USB) and P1394. Such an interface circuit is not only user-friendly, but is also flexible and readily expandable. The PnP interface circuit is also superior to the RS-232 and RS-422 in data transmission speed and bandwidth.
A common USB connection architecture is to connect peripheral devices to a USB controller of a host machine, such as a personal computer, by means of at least one hub which comprises an interface circuit to serve as a multiplexer between the peripheral devices and the host machine. Each time a peripheral device is connected to the hub, operation system of the host machine assigns a communication port, such as COM1, COM2, COM3, to the peripheral device through which drive program of the peripheral device access the peripheral device. The assignment of the communication port is performed by the host machine and a user of the computer system has no way to known. This causes problems for a user to efficiently and fully exploit the resources of the computer system.
Sometimes, it is possible for the user to get access to the communication port information of a peripheral device connected to the USB hub by means of a complicated software operation of the host computer. However, it requires skilled persons to perform such operations and thus causes inconvenience. Furthermore, it is not possible heretofore for the user to directly get aware of the communication port information from the corresponding peripheral device. This is particular inconvenient in an industrial control system in which peripheral devices may be located far away from the host machine. Without being capable to get aware of the communication port information from each peripheral device, the user must get back to the host machine to access the information. This is very troublesome for the user in installing the system. In addition, to get the information of the communication ports of the peripheral devices from the host machine as is adapted in the prior art, the peripheral devices must be of different types, otherwise it would be even more difficult to understand the association of each communication port with the peripheral devices and it is impossible to monitor the operation of the system.
It is thus desirable to provide a PnP interface circuit incorporating visual display device for overcoming the problems discussed above.
Accordingly, an object of the present invention is to provide a plug-and-play interface circuit incorporating a visual display device therein for directly displaying in a peripheral device the communication port information thereof.
Another object of the present invention is to provide a plug-and-play interface circuit comprising a visual display device for instantly displaying the connection status of a corresponding peripheral device to a host machine.
A further object of.the present invention is to provide a plug-and-play interface circuit comprising an input device thereby allowing a user to directly enter command for dynamically modifying and changing communication port information of a peripheral device.
To achieve the above objects, in accordance with the present invention, there is provided a plug-and-play interface circuit comprising a basic plug-and-play circuit and a visual display device connected to a microprocessor of the basic plug-and-play circuit for displaying communication port information of a peripheral device connected thereto. An input device is connected to the microprocessor for receiving user""s instruction to modify and change the communication port information of the corresponding peripheral device. A memory stores static display information, such as display format and fonts. The memory is controlled by the microprocessor to provide the static display information to the display device for being displayed together with the communication port information.